Drive belts for vehicle accessories in motor vehicles have long been used in the automotive industry for supplying power from a pulley connected to the engine crankshaft to the various accessories of the vehicles such as the air conditioning unit, water pump, alternator, and the like. Recently a single drive belt has been used to operate the various accessories by engagement with a pulley mounted on each of the shafts of the various accessories. With the advent of the single accessory drive belt, belt tensioners are becoming more important for maintaining a proper tension on the drive belt throughout the life of the belt. These belt tensioners come in a variety of constructions and modes of operation. One of the more common belt tensioner uses an idler pulley which is mounted on a lever arm which is pivotally mounted on a supporting bracket or base member attached to the vehicle. One type of such a belt tensioner in which the self-aligning bolt of the invention is adapted for use is shown in U.S. Pat. No. 4,551,120.
It is imperative in the mounting of the idler pulley lever arm on the base member that the pivot bolt for the arm be accurately aligned and perpendicular to the lever arm. Any misalignment will cause excess wear on a bearing which pivotally mounts the lever arm on the bolt as well as excess wear of the bearing which rotatably mounts the idler pulley on an extended end of the lever arm. Such wear shortens the life of the idler pulley, pivot bolt and associted bearings. Also, any slight misalignment of the pivot bolt and lever arm can cause the belt to become disengaged from its contact surface of the idler pulley. Likewise, such misalignment of the idler pulley lever mounting arm with its pivot bolt will appreciably shorten the life of the drive belt. It is also a problem in certain belt tensioners that the pivot bolt after extended periods of use will back out or become disengaged from the base member by the vibrations continuously exerted thereon. Therefore, it is imperative that the lever arm be properly aligned with the pivot bolt on which it is mounted as well as the pivot bolt be accurately installed in the base member or attachment bracket.